In recent years, the population of people exhibiting symptoms of diabetes, hypertension, hyperlipemia, arteriosclerosis and other diseases and conditions that are referred to as “diseases associated with adult lifestyle habits” has been increasing in Japan as a result of westernization of traditional lifestyle habits. In particular, cardiovascular diseases and cerebrovascular diseases account for approx. one-third of all deaths, and this ratio is increasing each year. Accordingly, implementing measures to address these diseases has become a national challenge. With these arteriosclerotic diseases, the risk of pathogenesis increases significantly when hypertension, hyperlipemia, glucose tolerance dysfunction and other risk factors accumulate. The condition where these risk factors have accumulated is called the “Metabolic Syndrome,” which is a widely recognized medical condition.
According to a study of 120,000 Japanese working at corporations, those who have at least one of the risk factors “Obesity,” “Hypertension,” “High blood sugar,” “High triglyceride (neutral fat) blood disease” and “Hypercholesterolemia” are said to have a five times higher risk of developing heart diseases. The risk of heart diseases increases ten-folds with those having two risk factors, and it rises as much as 31 times with those having three to four risk factors. According to a study conducted by the Ministry of Health, Labour and Welfare of Japan, there are reportedly 39 million people suffering from hypertension, 22 million people suffering from hyperlipemia, 1.62 million people suffering from diabetes (including those not currently suffering from diabetes but presenting higher risks of developing one), and 4.68 million people suffering from obesity. The numbers of these patients are increasing each year.
The metabolic syndrome is a “Multiple risk factor syndrome that tends to cause arteriosclerosis, characterized by accumulation of visceral fat as well as by association with multiple diseases including insulin resistance, anomaly of saccharometabolism, lipid metabolism abnormality and hypertension resulting from accumulation of visceral fat.” An accumulation of visceral fat is the very fundamental cause of the metabolic syndrome. Fat tissues, which are secretory tissues covering the largest area in the living body, produce various endocrine factors and play a part in the maintenance of homeostasis in the living body. However, studies have revealed that an excessive accumulation of visceral fat can tip the secretion balance of endocrine factors and cause various diseases and conditions. In particular, certain endocrine factors such as plasminogen activator inhibitor (PAI-1), tumor necrotizing factor (TNF-α), reptin, etc., are secreted in greater amounts as visceral fat accumulates, and higher secretion levels of these endocrine factors cause thrombosis, insulin resistance, anomaly of saccharometabolism, hypertension, and so on.
In the meantime, adiponectine, which is uniquely secreted by fat tissues, is normally present at a high concentration in blood streams. It is known that when visceral fat accumulates, the concentration level of adiponectine decreases. Adiponectine is known to have various physiological functions such as anti-diabetic action, anti-arteriosclerotic action, anti-inflammatory action, and anti-hypertensive action, and therefore it is very important to promote an increase in the adiponectine level in blood streams, or suppress a decrease in the adiponectine level in blood streams, in order to prevent/treat the metabolic syndrome.
Drug therapies have traditionally been used to counter the individual diseases and conditions caused by the metabolic syndrome, but these therapies present problems in that, among others, they require prescriptions and also accompany side effects. In addition, it has been shown that even when one disease or condition is treated, other disease or condition may develop into a serious state. Accordingly, it is necessary to adjust the secretion balance of endocrine factors which are derived from fat cells present upstream of these conditions.
In view of the above, it is considered more important to change our daily lifestyle habits such as exercise and diet, rather than resorting to drag therapies, in the prevention/treatment of the metabolic syndrome caused by an accumulation of metabolic fact. For this reason, drugs, beverages, foods or feeds that are effective in preventing/treating the metabolic syndrome caused by an accumulation of visceral fat—products that can be taken daily and over a long period of time without presenting safety risks—are being desired.
As for the application of lactic bacteria as effective ingredients that act upon human health, Patent Literature 1 reports that lactic bacteria belonging to the Lactobacillus acidophilus complex, which are classified as Lactobacillus acidophilus, Lactobacillus crispatus, Lactobacillus amylovorus, Lactobacillus gasseri, Lactobacillus gallinarum or Lactobacillus johnsonii and has affinity with asialo GM1, as well as extracts of these lactic bacteria, are effective in preventing the infection of pathogens having affinity with asialo GM1.
Also, Patent Literature 2 reports that fungus bodies of Lactobacillus gasseri or fermentation products thereof are effective ingredients of preventive/treatment drugs for inflammatory bowel diseases as well as for the irritable bowel syndrome. Furthermore, Patent Literature 3 describes a drug to prevent/improve/treat diabetic complications whose effective ingredient includes lactic bacteria belonging to the Lactobacillus gasseri group and cultures thereof, as well as lactic bacteria belonging to the Bifidobacterium longum group and cultures thereof.
Among drugs whose effective ingredients are fungus bodies and cultures obtained by culturing lactic bacteria belonging to the Lactobacillus gasseri group, a drug to suppress rise in serum cholesterol level is described in Patent Literature 4, in addition to the above. Also, Patent Literature 5 describes an osteoclastic inhibitor, where its effective ingredient includes fungus bodies and cultures thereof obtained by culturing lactic bacteria belonging to the same Lactobacillus gasseri group, along with a beverage, food or feed having a bone absorption suppression action. Patent Literature 6 describes an immunologic enhancement agent and an immunologic enhancement beverage or food, each of which does not contain lactic bacteria belonging to the Lactobacillus gasseri group alone, but instead blends lactic bacteria belonging to the Lactobacillus gasseri group with grains of oat and other members of the Gramineae family as well as processed products made from these grains, where the aforementioned document shows that blending these ingredients activates macrophages more and increases the cytokine production in a synergistic manner to increase the immunologic enhancement effect. However, it is not known that cultures of Lactobacillus gasseri, or fungus bodies themselves, have a visceral fat reducing action.
On the other hand, Lactobacillus helveticus, which is a lactic bacterium in the Lactobacillus sp. and has been used as a representative lactic bacteria starter for dairy products for many years, has strong protein decomposition activity and in particular, the extracellular proteinase of Lactobacillus helveticus which exhibits especially high activity has an important action on the fermentation property of milk. To be specific, this extracellular proteinase decomposes lactoprotein and produces various types of peptide fragments. The produced peptides then receive actions of a group of peptitases and further change themselves into peptides of lower molecular weights. It is known that some of the peptides produced in the culture medium due to the actions of a group of proteolytic enzymes are taken into the fungus bodies of lactic bacteria and utilized as a source of nitrogen.
On the other hand, it is reported in Non-patent Literature 1 that some of the peptides produced in the culture medium have an activity to inhibit the angiotensin converting enzyme (hereinafter referred to as “ACE”) which is a substance that causes rise in blood pressure. As for peptides intended to inhibit the enzymatic activity of ACE and thereby suppress rise in blood pressure, many effective peptides have already been reported that are produced from lactoprotein, soybean protein or fish/meat protein decomposition products, etc. Among others, the peptides with ACE inhibition activity contained in fermented milk made with Lactobacillus helveticus have been revealed as Val-Pro-Pro and Ile-Pro-Pro, and these lactotripeptides have been shown to present a strong hypotensive action in an experiment using rats with naturally induced hypertension (SHR), according to Non-patent Literature 2. As just described, functional foods containing acid milk that has been fermented by Lactobacillus helveticus are also shown to have not only a hypotensive activity, but also a stress relieving action, in Non-patent Literatures 7 and 8. In addition, lactic bacteria such as Lactobacillus helveticus, Lactobacillus casei, L. delbrueckii subsp. bulgaricus, L. delbrueckii subsp. lactis, etc., are shown to provide an immunostimulation action in Patent Literature 9.
However, it is not known that the fungus bodies of these lactic bacteria themselves, or cultures thereof, have a visceral fat reducing action.
Lactococcus lactis or Lactococcus cremoris are lactic bacteria which are widely used in the manufacture of milk products. However, not much is known about the physiological functions of these lactic bacteria. Although lactic bacteria belonging to the Lactococcus sp. are known to produce γ aminobutyric acid (GABA) and the like through fermentation of milk, soybean milk, pickles, etc., to finally demonstrate a blood pressure adjusting action, etc., it is not known that these lactic bacteria contribute to the reduction of visceral fat.    Patent Literature 1: Japanese Patent Laid-open No. Hei 8-268899    Patent Literature 2: Japanese Patent Laid-open No. 2003-95963    Patent Literature 3: Japanese Patent Laid-open No. 2003-252770    Patent Literature 4: Japanese Patent Laid-open No. 2003-306436    Patent Literature 5: Japanese Patent Laid-open No. 2004-315477    Patent Literature 6: Japanese Patent Laid-open No. 2006-69993    Patent Literature 7: Japanese Patent Laid-open No. Hei 10-45610    Patent Literature 8: Japanese Patent Laid-open No. Hei 11-98978    Patent Literature 9: Japanese Patent Laid-open No. 2006-76961    Non-patent Literature 1: J. Dairy Sci., 78: 777-783 (1995)    Non-patent Literature 2: J. Dairy Sci., 78: 1253-1257 (1995)